The effect of temperature on the clearance of intraperitoneally-injected gonadotropin in the goldfish Carassius auratus

The serum half-disappearance time ($\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$), metabolic clearance rate and volume of distribution of intraperitoneally administered carp gonadotropin (cGtH) and endogenous GtH levels were determined in sexually mature male and female goldfish, Carassius auratus maintained at 12 ± 1°C or 20 ± 1°C. The results indicated that the rate of serum uptake of the injected cGtH from the peritoneal cavity was greater at 20°C than at 12°C in sexually mature male goldfish. Although increased endogenous serum GtH levels and decreased values of serum $\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ were associated with the elevated temperature, there was no difference in any of the parameters between sexually mature male and female goldfish acclimated to 12°C.     

Morphological studies of peripheral blood cells of the Chinese sturgeon, <Emphasis Type="Italic">Acipenser sinensis</Emphasis>

The peripheral blood cells of one-year-old Chinese sturgeon (Acipenser sinensis) have been studied by light microscopy and transmission electron microscopy. The erythrocyte count was 84.86 × 10⁴ cell mm⁻³ in the peripheral blood of the fish and that of leukocytes was 2.24 × 10⁴ cell mm⁻³. The erythrocytes and four main types of leucocyte—thrombocytes, lymphocytes, granulocytes (including neutrophils and eosinophils), and monocytes, were identified in the peripheral blood. In addition to normal erythrocytes, reticulocytes and division of erythrocytes were observed. Thrombocytes were the most numerous among the leukocytes, and the number of neutrophils with lobated nuclei was larger than for other fish. The structures of the erythrocytes, lymphocytes, monocytes, granulocytes, and thrombocytes of the fish were studied. The erythrocytes were almost completely devoid of organelles, except for some mitochondria and granules. A large number of vacuoles and a few organelles were observed in cytoplasm of the monocytes. There were many microvilli on the membrane and pseudopodia-like cytoplasm bulge in the lymphocytes. The neutrophils were round or oval in shape with bilobed, trilobed, or multilobed nuclei whereas the eosinophils had big special granules, dark stained. There were many vesicles in some thrombocytes, which were related to its phagocytosis; some thrombocytes had almost no cytoplasm or organelles.     

Changes in density of under-yearling masu salmon <Emphasis Type="Italic">Oncorhynchus masou</Emphasis> in a natural stream after release

ABSTRACT:   The relation between the density of fish and parameters such as body weight, condition factor and the hepatic triglyceride (TG) content of masu salmon Oncorhynchus masou juveniles after release into a natural stream were studied. Hatchery-reared juveniles of different sizes and numbers were released in May 1999, 2000 and 2001, and investigations were carried out from July to September each year. The density of fish was relatively high in 1999, when juveniles of the largest size and number were released, but then continued to decrease during the investigation. The hepatic TG content remained considerably low in 1999, and there was a significant negative correlation between the density of fish and the hepatic TG content of the juveniles caught over three years. The initial fish size and number at release as well as the nutritional condition of the juveniles may affect the density of fish after release.     

Willingness to travel to avoid recreation conflicts in Danish forests

Conflicts among forest visitors have direct effects on the quality of a recreational experience. As the number of visitors to forests close to residential areas increases, as well as the number of different activities, so does the potential for perceived conflicts. According to the literature, expanding knowledge of conflict characteristics and their causes is important for recreation planners and managers who aim to reduce conflicts.In the present study, different forest user groups were identified and categorised according to their pursued activities, and for each group, causes of conflict were identified. Furthermore, a choice experiment was constructed to estimate the distance visitors are willing to travel to encounter few visitors as opposed to many visitors, and thereby potentially experience fewer conflicts. Comparing the marginal willingness to travel (WTT) of different user groups suggests that some groups have a WTT further than the average to reach a forest with ‘Few’ visitors. The average WTT to reach a forest area with ‘Few’ visitors. ‘Mountain bikers,’ ‘Peace and nature lovers’ and ‘Horse riders’ are willing to travel 4 km more than the average per visit to reach a less crowded forest. At the other end of the scale, we find that people who are doing physical exercise are willing to travel 2 km less than the average to reach a less crowded forest.     

Genetic identification of native populations of fluvial white-spotted charr <Emphasis Type="Italic">Salvelinus leucomaenis</Emphasis> in the upper Tone River drainage

ABSTRACT:   Stocking of exogenous, hatchery-reared white-spotted charr Salvelinus leucomaenis has been conducted throughout much of their range in Honshu Island, Japan, to increase angling opportunities. Although the native charr populations are thought to have declined because of hybridization with introduced fish, their distribution and genetic status have been uncertain. Fine population structures of charr in the upper Tone River drainage were examined using mitochondrial DNA and microsatellite analyses so as to clarify the presence of native populations. One common mtDNA haplotype was detected in all populations in the Ohashi River and Watarase River, and four and one tributary populations were monomorphic for such haplotypes, respectively. However, several haplotypes, considered to have originated from stocked hatchery fish, were observed in the stocked and the remaining populations. Judging from the genetic integrity over a fine geographic scale, the former were considered as indicative of native populations and the latter as admixtures with hatchery fish. Comparisons of genetic diversity, deviations from the Hardy–Weinberg equilibrium, principal component analysis, and relatedness estimations based on microsatellite DNA can also provide evidence for distinguishing native populations from those influenced by hatchery fish.     

Rheological properties of pasta dough during pasta extrusion: Effect of moisture and dough formulation

A study was conducted to investigate the effect of dough formulation and hydration level on the rheological properties of pasta dough during pasta extrusion. Semolina 100%, whole wheat 100%, and the following mixtures semolina-whole wheat (49:51), semolina-flaxseed flour (90:10), whole wheat-flaxseed flour (90:10), and semolina-whole wheat-flaxseed flour (39:51:10) were the formulations used for the experiments. Dough was hydrated at 30, 32, and 34% moisture content. Pasta was extruded with a capillary and a semi-commercial pasta extruder to determine the apparent viscosity of the dough during extrusion conditions and its relationship to the behavior of the dough during pasta processing. Results showed that non-traditional pasta dough behaved like a shear thinning fluid that can be described by the Power Law model. Increased hydration levels and/or presence of flaxseed flour on the dough formulation decreased the apparent viscosity of the dough, which correlated with extrusion pressure, mechanical energy, and specific mechanical energy that were required to extrude the dough in the pasta extruder. The strong correlations found between the apparent viscosity of the dough and the pasta extrusion parameters indicates the possibility of using a capillary rheometer to determine the appropriate hydration level of ingredient formulations before extruding with a pasta press.     

Pseudaboydins A and B: Novel Isobenzofuranone Derivatives from Marine Fungus Pseudallescheria boydii Associated with Starfish Acanthaster planci

Two novel isobenzofuranone derivatives, pseudaboydins A (1) and B (2), along with five known compounds, including (R)-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5-hydroxybenzofuran (3), (R)-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5-methoxybenzofuran (4), 3,3′-dihydroxy-5,5′-dimethyldiphenyl ether (5), 3-(3-methoxy-5-methylphenoxy)-5-methylphenol (6) and (−)-regiolone (7), were isolated from the culture broth of the marine fungus, Pseudallescheria boydii, associated with the starfish, Acanthaster planci. Their structures were elucidated primarily based on NMR and MS data. The absolute configurations of 1–4 were determined by CD spectroscopy and single-crystal X-ray diffraction studies. The cytotoxic and antibacterial activities of 1–4 were evaluated. Pseudaboydin A (1) showed moderate cytotoxic activity against human nasopharyngeal carcinoma cell line HONE1, human nasopharyngeal carcinoma cell line SUNE1 and human glandular lung cancer cell line GLC82 with IC₅₀ values of 37.1, 46.5 and 87.2 μM, respectively.     

Microbial diseases of cultured lobsters: A review

Six microbial diseases of cultured American lobsters (Homarus americanus) determined to be of significant concern to commercial aquaculture are discussed in relation to present knowledge of characteristics of the causative microorganisms, lobster susceptibility, environmental influence, severity, gross and microscopic recognition, physiological changes, contagion and control. The diseases reviewed here include shell disease, Gaffkemia, microbial epibiont disease, Lagenidium disease, Haliphthoros disease, and Fusarium disease.